Metformin blocks the absorption of vitamin B12 through a mechanism that has not been established but could be because of interference with the calcium‐dependent binding of the intrinsic factor ...vitamin B12 complex to the cubam receptor in the terminal ileum. The subsequent deficiency of vitamin B12 may cause or accelerate distal symmetrical and autonomic neuropathy in the patient with diabetes. Several observational studies and meta‐analyses have reported a significant association between metformin utilization and vitamin B12 deficiency. Prospective studies have shown that not only do metformin utilizers have lower vitamin B12 levels but they also have higher frequencies of distal symmetrical polyneuropathy and autonomic neuropathy (including cardiac denervation, which is associated with increased incidences of cardiac arrhythmias, cardiac events and mortality). Therefore, periodic monitoring of vitamin B12 is recommended in all patients who utilize metformin, particularly if metformin has been used for over 5 years at which stage hepatic stores of vitamin B12 would probably be depleted. Factors that accelerate the loss of hepatic vitamin B12 stores are proton pump inhibitors, bariatric surgery, being elderly and having an increased turnover of red blood cells. If serum vitamin B12 levels are borderline, measurement of methylmalonic acid and homocysteine levels can detect vitamin B12 deficiency at its earliest stage. Therapies include prophylactic calcium and vitamin B12 supplements, metformin withdrawal, replenishing vitamin B12 stores with intramuscular or oral vitamin B12 therapy and regular monitoring of vitamin B12 levels and vitamin B12 supplements if metformin continues to be utilized. With adequate vitamin B12 replacement, while symptoms of neuropathy may or may not improve, objective findings of neuropathy stabilize but do not improve.
The prevalence of vitamin B12 deficiency is high in at-risk populations with sometimes irreversible consequences. Beside total B12 (TVB12), active B12 (AVB12) is a promising first-line marker. Only ...Abbott AVB12 assays were largely evaluated and generally demonstrated benefit in clinical practice. More recently developed Roche AVB12 still requires some investigations.
Our study aimed to evaluate the Roche Elecsys® AVB12 immunoassay performance versus Roche Elecsys® TVB12 competition assay.
and Methods: We included 175 patients at Rouen University Hospital who had a TVB12 value <300 pmol/L. We evaluated performance of AVB12 by comparing the results with TVB12 and MMA values in case of disagreement.
Positive correlation was found between the AVB12 and TVB12. We found a disagreement between TVB12 and AVB12 in 18.8% of cases. Among 33 cases of disagreement, 76% had normal AVB12 but low TVB12, whereas 24% had low AVB12 and normal TVB12. Thirty-one MMA determinations were performed: 71% showed agreement between MMA and AVB12, versus 29% between MMA and TVB12. TVB12 reported a sensitivity (Se) at 66.7%, specificity (Sp) at 20%, positive predictive value (PPV) at 16.7% and negative predictive value (NPV) at 71.4% for the prediction of MMA elevation. We determined an optimized cut-off value of 45.5 pmol/L for AVB12, which reported a Se 66.7%, Sp 60%, PPV 30.7%, and NPV 88.9%.
Our results provide preliminary evidence that Roche AVB12 may offer better discrimination than Roche TVB12 in the diagnosis of vitamin B12 deficiency. Further more detailed evaluation is warranted.
Background
Lingual linear lesions (LLLs) are the oral linear lesions located on the dorsum, lateral borders, and/or ventral surface of tongue. It has been suggested that LLLs might be an early ...clinical sign of vitamin B12 deficiency. Here, a retrospective study was conducted to further investigate and validate the association between LLL and vitamin B12 deficiency.
Methods
Based on the clinical examination, patients with LLLs were enrolled and analyzed retrospectively. Data regarding clinical and laboratory features were obtained. Follow‐up was done at least 6 months following appropriate supplementation therapy.
Results
A total of 57 patients, consisting of 20 males and 37 females with a mean age of 59.12 years (range, 18–80), were enrolled in this study. The hematological examination revealed that 56 (98.25%) of the 57 patients had severe serum vitamin B12 deficiency, and the other 1 patient had a borderline low level of vitamin B12. All the enrolled patients responded well to cobalamin replacement therapy.
Conclusion
LLLs might be a clinical sign strongly suggestive of severe vitamin B12 deficiency.
Cyanide poisoning poses a significant threat to burn patients exposed to smoke in residential or workplace fires, leading to central nervous system dysfunction, hemodynamic instability, ...cardiovascular collapse, and death. Prompt administration of an effective antidote is critical. Hydroxocobalamin, a form of vitamin B12, is the gold standard treatment for cyanide toxicity, by binding to cyanide molecules and converting them into non-toxic cyanocobalamin that is eliminated by the kidneys. This mechanism is distinct from previous cyanide antidotes, which induce the formation of methemoglobin to bind to cyanide. Recent case studies have reported elevated methemoglobin levels after hydroxocobalamin administration, raising concerns regarding its safety. The current study investigates smoke inhalation patients treated with hydroxocobalamin at a single institution Burn Unit in hopes of enhancing our understanding of the complexities surrounding cyanide antidote therapy.
After Institutional Board Approval, a retrospective cohort study was conducted. Our sample comprised burn patients with inhalation injury admitted to a single institution from 2013 to 2023 and treated with hydroxocobalamin for suspected cyanide toxicity. We also analyzed a matched control cohort of similar patients with inhalation injury not treated with hydroxocobalamin. We analyzed changes and peaks in methemoglobin levels, lactate levels, blood urea nitrogen (BUN) and creatinine, ventilator days, % total body surface area (TBSA), various types of medications and dressings, and mortality. Statistical analyses included t-tests, chi-square, linear and logistic regressions, and correlation analysis.
In the study, 36 patients with suspected inhalation injury were treated with hydroxocobalamin at the Los Angeles General (LAG) Burn Unit from 2013 to 2023, who were matched to 32 control patients with inhalation injury who were not treated with hydroxocobalamin. Demographic and baseline characteristics showed no statistically significant differences between the groups, including age, gender, BMI, and %TBSA. No significant differences were found in initial, final, peak, or change in methemoglobin levels. The study also revealed no significant disparities in initial lactate levels, mortality, kidney function tests, ventilator days, surgeries, or use of medications/treatments (e.g., Silvadene dressings, Vitamin C) between the two groups. When controlling for covariates, multiple linear regression analysis (age, gender, and %TBSA) indicated that hydroxocobalamin administration was not significantly associated with changes in methemoglobin or mortality. Increased %TBSA, however, was linked to elevated lactate levels.
Our investigation sought to assess the potential risks associated with hydroxocobalamin administration in burn patients with concomitant inhalation injury. Contrary to our initial hypothesis, we found no statistically significant differences in methemoglobinemia, lactate levels, mortality, or kidney function. The influence of other factors, such as methemoglobinemia-inducing drugs or hydroxocobalamin's interference with co-oximetry, adds complexity. Although elevated methemoglobin levels were observed in some cases, their clinical significance was limited. However, this study's limitations, particularly the rarity of inhalation injury cases with concern for cyanide toxicity, warrant consideration. Further research is required to comprehensively elucidate the impact of hydroxocobalamin administration on burn patients' outcomes.
•Hydroxocobalamin is a common antidote for suspected inhalation injury in burn patients.•Hydroxocobalamin does not lead to methemoglobinemia or increased mortality.•Hydroxocobalamin does not lead to significant changes in outcomes for burn patients.
Nutrition plays a crucial role in the development and health of the human brain, from early stages to adulthood. The complex process of neurodevelopment necessitates interaction among various ...factors, with balance in the concentration of vital macronutrients and micronutrients being essential. Regarding micronutrients, vitamin B12 stands out, playing a vital role in the development and functioning of the motor nervous system. The objective was to investigate the influence of reduced levels of vitamin B12 on infant motor development and analyze the effects of supplementation on this aspect of development.
For this purpose, the criteria of the PRISMA method and registration in the PROSPERO database were used. The search was conducted in the following databases: PubMed (Medline), Scopus, PsycINFO, Web of Science, and ScienceDirect. A total of 684 records were initially identified.
Of the eight included articles, there was diversity regarding geographical contexts and study designs. The final sample comprised a total of 1,559 participants of both sexes. Studies aimed at correcting low levels of vitamin B12 opted for supplementation, following various protocols that varied in dose, administration method, and duration. At the end of the studies, the serum level of this vitamin ranged from 131 pmol/L to 1141 pmol/L.
There is a complex array of factors contributing to reduced levels of vitamin B12, especially in the early stages of life, which significantly impacts infant motor development. Despite methodological variations among studies, evidence suggests that low levels of vitamin B12 may affect motor development and that supplementation could be an effective means of enhancing motor aspects in healthy children. However, due to the diversity of outcomes, it is important to promote comprehensive public policies to encourage appropriate interventions in this area.
Patients are at-risk for vitamin B12 deficiency after total gastrectomy due to a lack of intrinsic factors. The aim of the study was to clarify the clinical course and risk factors for vitamin B12 ...deficiency after total gastrectomy for gastric cancer patients.
Patients who underwent curative resection for gastric cancer were selected from the medical records of the Yokohama City University from 2000 to 2020. A logistic regression analysis was performed to identify risk factors for vitamin B12 deficiency.
We evaluated 47 patients. The median serum vitamin B12 levels before surgery were 359 pg/ml, while those at 3, 6, 9, and 12 months after surgery these were 255 pg/ml, 197.5 pg/ml, 195 pg/ml, and 206 pg/ml, respectively. Univariate analyses to identify factors associated with vitamin B12 deficiency at 6 months after surgery showed that the occurrence of postoperative complications was a significant risk factor (OR=6.347, 95%CI=1.607-25.774, p=0.009), while adjuvant chemotherapy was a marginally significantly risk factor (OR=3.562, 95%CI=0.877-14.477, p=0.076).
Almost half of the patients were diagnosed with vitamin B12 deficiency at 6 months after total gastrectomy for gastric cancer. In addition, the occurrence of postoperative complications and adjuvant chemotherapy were risk factors for vitamin B12 deficiency at 6 months after surgery.
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